Wednesday, August 29, 2012

Before getting in any details I must clarify: every plasma TV is made up of a glass plasma display and a plastic or tampered glass protective cover on top of it; what you touch at the front of a plasma TV is not the display itself, which is fairly thin and very fragile. What you touch is the protective glass, which serves dual function - protects the actual plasma display and protects the viewers from the radiation emitted by the display (a UV or other kind of filter - frankly I do not know what exactly, but it doesn't matter as long as you know it is meant to be there to serve such a purpose).

So this article is about the rare case of having an intact display and cracked or scratched protective layer.

This is much more rare than the opposite - intact protective layer and cracked/broken display, but just yesterday a walk-in customer proved it is not impossible to achieve.

How did his kids manage to do it I am still not sure, but he maintained they somehow did and as a result his 42'' Magnavox 42PF7220A/37 ended up with intact display and a cracked protective window, which, being thick and cracked, presented notable obstruction to proper viewing.

He asked if we have such a widow and of course was not surprised to find we didn't. He said he found one on eBay for about $270 or so, but of course that didn't make any practical sense.

So I looked around and simply offered him to use a protector from one of the many 42'' plasma TVs we had from about the same time , which had broken displays or were otherwise laying around waiting for better days to finally go to garbage.

In his case it was a Vizio P42HDTV10A I ended up giving him the window from.
I made $40 I would have otherwise dumped at the trash and he seemed happy too so I guess price was right for him as well.

He said it was slightly larger, but acceptable.

If you end up in the same boat just go to a few local TV shops and ask them for old units of the same size...I wouldn't pay more than $50 for one, $35 is probably more accurate if you have to do all the work to get the glass out.

Saturday, August 11, 2012

Note: below is a correspondence between us and a customer regarding his Samsung HP-T5064.

100% of what is said applies to the more popular model HP-T5054 as well as actually most other plasma TVs manufactured about the same time.

There's more to be said about them and I will maybe post another article about it, but this time the focus is on the common mistake I see of blaming the power board after reading a few misleading (and ofter confused by themselves) opinions by "experts" on sites like FixYa or Answer.com.

Customer:
Dear Coppell TV Repair,I have a Samsung
HP-T5064X/XAA and I believe I have a failed SMPS board, part
#BN44-00162A. I prefer to not replace individual components parts to
make the repair. Two questions:
1. Do you sell the SMPS board?
2. If not, can you repair the board if I bring it
in? (I'm a little west of Ft Worth.)

Coppell TV Repair:

1)Yes , I believe we have at least one at the moment. There are number of different board models
that would do the job and I know we have at least one in working mode, but I
also know I have at least three people about to drop by and maybe swap their
bad board (if bad) with a good one

2)Yes we do repair them whenever we can (we usually can). But the
really important question here is

3)Why do you think it is the power board that is bad and not ,
say, the trio of the Y-Main and the two buffers? Those fail way more often in
your TV.

Customer:

Thank you for responding so fast.

I confess to being fairly
electronics-dumb. My guidance so far has been reviewing help websites
(fixya) and going through others' troubleshooting steps. I'm pretty good
at soldering wires under the hood of a car, but soldering PCB is WAY beyond my
abilities. I was going to just replace the board rather than taking a
chance on replacing components and then burning out the board anyway.

Here's the rundown of the problem:

The entire screen unexpectedly
went black but sound remains. It appears black, not dim. I did the
usual "wait and retry" but there is no change.

I removed the back cover and
inspected the 4 main boards (left side, right side, inputs board at bottom
center, and the (SMPS board?) top center board that seems to be the master
board that all others feed from via flat cable. I see no signs of burning
or soot.

I removed the cable from
connection 807, plugged in power, turned on the TV and get normal start sound
(4 ascending notes) and typical 4 slow pulses of the blue light. No
change in black screen. I then turned off the TV and got the normal sound
(4 descending notes) and the blue light stays on as it usual. I unplugged
the TV and reconnected the 807. I repeated this process for the 808, 809,
and 810 cables. I got the same result every time. This lead me to
believe it is the SMPS board instead of one of the others.

I know that it is always a crap
shoot trying to "diagnose via email", but then again, I'm sure you
see this type of problem rather frequently. Are you open today? I'd
rather not bring in the whole TV if possible, can you advise me what board(s) I
should bring? I'm more than willing to swap out plug-in components if
that's what the repair entails, but when it comes to soldering boards, I'd
rather leave that to you professionals.

Thanks for your help. It is
a pleasure dealing with someone local.

Coppell TV Repair:

Well your conclusion is incorrect.

Based on what you say it is highly unlikely for your problem to
be in the power board.

First, if the power board does not produce the output voltages
it is supposed to produce then its own control logic will catch the event and
shut it off to prevent further damage.

The bare fact that the TV comes on and stays on (even without an image)
suggests the power board is just fine.

Second, the description you give is the most common one for a
typical failure in the Y-Main board and buffers , which I told you is the most
popular in those TV – the unit comes on with no screen.

I don’t have the board handy (I am at home now), but when the
Y-Main is bad there are a number of connectors you can disconnect and the
result would still be the same – the TV would come on with no display.

Imagine removing the wheels on a car that does not turn on
because of whatever problem with the starter; it would still not start, right?
You could also remove the alternator to the same effect J

You are looking at about $240 in fixes and that’s if you bring
the Y-Main board and the two buffers to us. The Y-Main will have to be repaired
and the two buffer boards will most likely need to be replaced.

This explanation alone is well worth $20?

Isn’t it? :-)

Follow-up for the online post:Hope this helps avoid this common confusing and save a little time and a few bucks.

Prices will sure change over time, but it is highly unlikely that they will go up in the near future.

We are well aware they are too high even right now, the problem is that the new buffer boards are very expensive still...and we know from long and bitter experience that this particular failure better be done right and expensive than cheap.